Division 3.2 Option 2: Measurement of the torque independent losses, measurement of the torque loss at maximum torque and interpolation of the torque dependent losses based on a linear model

United Kingdom

Option 2 describes the determination of the torque loss by a combination of measurements and linear interpolation. Measurements shall be performed for the torque independent losses of the transmission and for one load point of the torque dependent losses (maximum input torque). Based on the torque losses at no load and at maximum input torque, the torque losses for the input torques in between shall be calculated with the torque loss coefficient f_Tlimo .

The torque loss T_l,in on the input shaft of the transmission shall be calculated by

T_l,in (n_in , T_in , gear) = T_{l,in,min_loss} + f_Tlimo * T_in + T_{l,in,min_el} + f_{el_corr} * T_in

The torque loss coefficient based on the linear model f_Tlimo shall be calculated by

f_{Tlimo} = \frac{T_{l,maxT} - T_{l,in,min_loss}}{T_{in,maxT}}

where:

T_l,in

Torque loss related to input shaft [Nm]

T_{l,in,min_loss}

Drag torque loss at transmission input, measured with free rotating output shaft from testing without load [Nm]

n_in

Speed at the input shaft [rpm]

f_Tlimo

Torque loss coefficient based on linear model [-]

T_in

Torque at the input shaft [Nm]

T_in,maxT

Maximum tested torque at the input shaft (normally 100 % input torque, refer to 3.2.5.2. and 3.4.4.) [Nm]

T_l,maxT

Torque loss related to input shaft with T_in = T_in,maxT

f_{el_corr}

Loss correction for electric power loss level depending on input torque [-]

T_l,in,el

Additional torque loss on input shaft by electric consumers [Nm]

T_{l,in,min_el}

Additional torque loss on input shaft by electric consumers corresponding to minimum electric power [Nm]

The correction factor for the torque dependent electric torque losses f_{el_corr} and the torque loss at the input shaft of the transmission caused by the power consumption of transmission electric auxiliary T_l,in,el shall be calculated as described in paragraph 3.1.